This invention relates generally to methods for the modification of textile and other materials, for example by the attachment of hydrophobic moieties, to impart properties thereon such as water repellency and permanent press.
Most chemical research in the textile field was conducted in the 1950s, 60s, and 70s. This work has been extensively reviewed. For example, see: Smith and Block, Textiles in Perspective, Prentice-Hall, Englewood Cliffs, N.J., 1982; Handbook of Fiber Science and Technology, Marcel Dekker, New York, N.Y., Vols. I-III, 1984; S. Adanur, Wellington Sears Handbook of Industrial Textiles, Technomic Publishing Company, Inc., Lancaster, Pa., 1995; and Philip E. Slade, Handbook of Fiber Finish Technology, Marcel Dekker, New York, 1998). A large majority of this published research was never commercialized due to inhibitory costs or the impracticality of integration into textile production processes. There has been less research in this area in recent years. Most current work is centered on optimizing existing technology to reduce costs and comply with recent government regulations.
Methods have been developed in the art for making textile materials water repellent. The terms xe2x80x9cwater repellentxe2x80x9d and xe2x80x9cwaterproofxe2x80x9d are distinguishable as related to textiles. Water repellent fabrics generally have open pores and are permeable to air and water vapor. Waterproofing involves filling the pores in the fabric with a substance impermeable to water, and usually to air as well. For the purpose of everyday clothing, water repellent fabric is preferable because of the comfort afforded by the breathability of the clothing.
Current commercial processes for producing water repellent fabrics are based on laminating processes (C. J. Painter, Journal of Coated Fabrics, 26:107-130 (1996)) and polysiloxane coatings (Philip E. Slade, Handbook of Fiber Science and Technology, Marcel Dekker, New York, N.Y., Vol. II, 1984, pp. 168-171). The laminating process involves adhering a layer of polymeric material, such as Teflon(copyright), that has been stretched to produce micropores, to a fabric. Though this process produces durable, water repellent films, it suffers from many disadvantages. The application of these laminants requires special equipment and therefore cannot be applied using existing textile processes. Production of the film is costly and garments with this modification are significantly more expensive than their unmodified counterparts. The colors and shades of this clothing can be limited by the coating laminate film color or reflectance. Finally, clothing made from this material tends to be heavier and stiffer than the untreated fabric. This material also can be disadvantageous due to mismatched expansion and shrinkage properties of the laminate. Polysiloxane films suffer from low durability to laundering which tends to swell the fabric and rupture the silicone film.
Methods of imparting hydrophobic character to cotton fabric have been developed including the use of hydrophobic polymer films and the attachment of hydrophobic monomers via physi- or chemisorptive processes. Repellents used based on monomeric hydrocarbon hydrophobes include aluminum and zirconium soaps, waxes and waxlike substances, metal complexes, pyridinium compounds, methylol compounds, and other fiber reactive water repellents.
One of the earliest water repellents was made by non-covalently applying water soluble soap to fiber and precipitating it with an aluminum salt. J Text. Res. 42:691 (1951). However, these coatings dissolve in alkaline detergent solution, therefore washfastness is poor. Zirconium soaps are less soluble in detergent solutions (Molliet, Waterproofing and Water-Repellency, Elsevier Publ. Co., Amsterdam, 1963, p. 188); however, due to the non-covalent attachment to the fabric, abrasion resistance and wash fastness are poor. Fabric also has been made water repellent by coating it with a hydrophobic substance, such as paraffin. Text. Inst. Ind. 4:255 (1966). Paraffin emulsions for coating fabrics are available, for example, Freepel(copyright) (BF Goodrich Textile Chemicals Inc., Charlotte, N.C.). Waxes are not stable to laundering or dry cleaning. Durability is poor due to non-covalent coating of the fabric and breathability is low.
Quilon chrome complexes polymerize to form xe2x80x94Crxe2x80x94Oxe2x80x94Crxe2x80x94 linkages (R. J. Pavlin, Tappi, 36:107 (1953)). Simultaneously, the complex forms covalent bonds with the surface of fibers to produce a water repellent semi-durable coating. Quilon solutions require acidic conditions to react thus causing degradation of the fiber through cellulose hydrolysis. Fabric colors are limited by the blue-green coloration imparted by the complex.
Pyridinium-type water repellents have been reviewed by Harding (Harding, J Text. Res., 42:691(1951)). For example, an alkyl quaternary ammonium compound is reacted with cellulose at elevated temperatures to form a durable water-repellent finish on cotton (British Patent No. 466,817). It was later found that the reaction was restricted to the surface of the fibers (Schuglen et al., Text. Res. J., 22:424 (1962)) and the high cure temperature weakened the fabric. Pyridine liberated during the reaction has an unpleasant odor and the fabric had to be scoured after the cure. The toxicological properties of pyridine ended its use in the 1970s when government regulations on such substances increased.
Methylol chemistry has been extensively commercialized in the crosslinking of cellulose for durable press fabrics. N-methylol compounds are prepared by reaction of an amine or amide with formaldehyde. Alkyl-N-methylol compounds can be reacted at elevated temperatures in the presence of an acidic catalyst with the hydroxyl groups of cellulose to impart durable hydrophobic qualities to cotton. British Patent Nos. 463,300(1937) and 679,811 (1952). The reaction with cellulose is accompanied by formation of non-covalently linked (ie., non-durable) resinous material, thus decreasing efficiency. In addition, the high temperature and acid catalyst reduces the strength of the fabric. Recently, the commercial use of methylol compounds has been decreasing due to concerns of toxic formaldehyde release from fabrics treated in such a manner.
Long-chain isocyanates have been used to hydrophobically modify cotton. British Patent No. 461,179 (1937); Hamalainen, et al., Am. Dyest. Rep., 43:453 (1954); and British Patent No. 474,403 (1937)). The high toxicity of isocyanates and significant side reactions with water, however, precluded it from commercial use. To circumvent the water sensitivity of isocyanates, alkyl isocyanates were reacted with ethylenimine to yield the less reactive aziridinyl compound which was subsequently reacted with cellulose. German Patent No. 731,667 (1943); and British Patent No. 795,380 (1958). Though the toxicity of the aziridinyl compound was reduced compared to the isocyanate, the procedure still required the handling of toxic isocyanate precursors. Also, the high cure temperature weakened the cellulose and crosslinkers were needed to increase structural stability. Alkyl epoxides have been reacted with cellulose under acidic or basic conditions to produce water repellent cotton. German Patent No. 874,289 (1953). Epoxides are, in general however, not very reactive and require long reaction times at high temperatures and therefore have not been extensively commercialized.
Acylation of cotton with isopropenyl stearate from an acidic solution of benzene and curing was used to produce a hydrophobic coating for cotton. U.S. Pat. No. 4,152,115. The high cure temperature and acid catalyst however weakens the cotton. This method disadvantageously uses carcinogenic and flammable solvents. The practicality of using flammable solvents in fabric finishings is limited. Alkyl vinyl sulfones have been reacted with cellulose in the presence of alkali to form a water repellent finish. U.S. Pat. No. 2,670,265. However, this method has not been commercialized because the alkali is not compatible with cross-linking reactants required for permanent press treatments.
Methods have been developed for imparting grease repellent properties to materials such as cotton. Perfluoroalkanoic acids have been applied in a variety of ways including as chromium complexes and as quaternary amines. U.S. Pat. No. 2,662,835; Phillips et al., Text. Res. J., 27:369 (1957); Tripp et al., Text. Res. J., 27:340 (1957); and Segal et al., Text. Res. J., 28:233 (1958). Since these finishes are non-covalently linked to the fabric, they are not durable to laundering. Attempts were made to covalently link fluorocarbons to cotton with perfluorinated acid chlorides in the presence of the base pyridine and dimethylformamide solvent (Benerito et al., Text. Res. J., 30:393-399 (1960)), however significant problems were encountered. The pyridine base formed an insoluble complex with the acid chloride that could only be overcome with the addition of large excesses of pyridine or the solvent dimethylformamide. Also, the finish was readily subject to hydrolysis and not durable to laundering. Repellent finishes made by reaction of glycidyl ethers of 1,1 -dihydrofluoroalkanols with cellulose (Berni et al., Text. Res. J;, 30:576-586 (1960)) produced a more durable finish, but required a reaction time of 30 h at 100xc2x0 C. and were not extensively commercialized. Interest in monomeric fluorocarbon finishes has been superseded by the use of fluorinated polymer films.
Methods also have been developed for modifying cotton by crosslinking in order to impart permanent press properties to the material. These methods have been reviewed in: R. M. Rowell and R. A. Young, Eds., Modified Cellulosics, Academic Press, New York, 1978; M. Levin and S. Sello, Eds., Handbook of Fiber Science and Technology, Vol. 2, Part A, Marcel Dekker, New York, 1984, pp. 1-318; and G. Hermanson, Bioconjugate Techniques, Academic Press, San Diego, Calif., 1996, pp. 169-297. The covalent crosslinks prevent the cellulose chains from slipping, thus imparting high durable press characteristics. However, the short and stiff crosslinks cause the cotton structure to become brittle and display poor tear strength. A variety of textile resins have been developed to crosslink cellulose and impart durable-press properties, such as polymethylol compounds formed by the reaction of aldehydes with amines. They include melamineformaldehyde (British Patent Nos. 458,877, 466,015 and 468,677), dimethylolethyleneurea (U.S. Pat. Nos. 2,416,046, 2,416,057, 2,425,627, 2,436,311, 2,373,136, and 2,899,263; and British Patent Nos. 603,160 and 577,735), and urons/triazones (U.S. Pat. Nos. 2,373,135; and 2,321,989; British Patent Nos. 575,260 and 845,468; German Patent No. 1,123,334; Angew. Chem., 60:267 (1948); Am. Dyest. Rep., 48:44 (1959); and Tex. Res J., 29:170 (1959).
Dimethyloldihydroxyethyleneurea (DMDHEU) has been used in the production of durable-press garments. Text. Res. J., 51:601 (1981). However, the DMDHEU system retains chlorine and causes yellowing and tendering of the cloth; therefore it is not suitable for use with white cloth. Resins have been developed specifically for use with white cloth that are esters of carbamic acid (carbamates). U.S. Pat. Nos. 3,639,455, and 4,156,784; Japanese Patent No. 599,505; British Patent Nos. 1,227,366, and 1,523,308; and French Patent Nos. 1,576,067 and 7,532,092. The crosslinking of the cellulose and polymerization of the resin generally occurs at the same time on the fabric. U.S. Pat. Nos. 5,447,537, 4,975,209, 4,936,865, 4,820,307, and 3,995,998.
Methods for modifying materials with reactive groups such as hydroxyls and amines have been developed in the art, however, materials with hydroxyl groups, including polysaccharides such as cellulose, have been found to be difficult to covalently modify and therefore require reactive modifiers or extreme conditions. Methods of reacting with hydroxyls that have been developed in the chemistry field include the use of acid chlorides, anhydrides, succinimides, and carbonyldiimidazole. See, e.g., J. March, xe2x80x9cAdvanced Organic Chemistry-Reactions, Mechanisms and Structure,xe2x80x9d, 3rd Ed., John Wiley and Sons, New York, 1995; and G. Hermanson, xe2x80x9cBioconjugate Techniques,xe2x80x9d Academic Press, Inc., San Diego, 1996.
There is a need for methods for modifying various substrate materials, such as textile fibers of cotton or other cellulosic materials, wool, silk and other proteinaceous fibers, and various other natural, man made, regenerated and synthetic fiber materials to alter and optimize their properties for use in different applications. There is a need for methods for improving the properties of cloth or fabric materials containing various natural, man made and/or synthetic fibers of various types, in order to improve various performance properties such as water resistance, soil resistance, speed of drying and permanent press properties. There further is a need for methods for producing modified textile fiber materials and other substrates which may be used in a wide range of applications including clothing and apparel fabrics, and various items of apparel, socks, hosiery, fabrics for footwear, shoes, home furnishing, fabrics for upholstery and window treatments including curtains and draperies, and fabrics for outdoor furniture and equipment, as well as for industrial textile end uses.
Provided are methods of modifying various substrate materials to alter the properties of the materials. In particular, compositions and methods are provided that permit the modification of a variety of textile fiber materials and similar substrates to alter properties including water repellency, grease repellency, soil resistance, oil or grease resistance, permanent press, detergent free washing, increased speed of drying, and improving strength and abrasion resistance. The methods also permit improvement of comfort of fibers, wherein the fibers are used alone or in combinations or blends with one or more others before or after treatment.
In one embodiment, provided are methods of modifying a material to increase its hydrophobicity as well as a variety of products obtained using the methods. A material comprising one or more modifiable functional groups is reacted with an activated hydrophobic acyl group, such as an acid chloride or anhydride, in the presence of a hindered base, to covalently attach the hydrophobic acyl group to the modifiable functional groups on the material. The presence of the hindered base advantageously neutralizes unwanted side reactions by acids such as HCl produced during the reaction.
The material which is modified may comprise a carbohydrate, and the modifiable functional groups on the material may comprise hydroxyls. Cellulose in natural or regenerated form may be modified by reacting it with an activated hydrophobic acyl group, such as an acid chloride or acid anhydride, in the presence of a hindered base, such as tripentylamine, to attach the acyl groups to the hydroxyls on the cellulose, to increase the hydrophobicity of the cellulose.
Cellulose may be reacted with an activated acyl group, such as an acid chloride, RCOCl, or anhydride, (RCO)2O, wherein R is a straight chain C8-C20 saturated hydrocarbon, for example a C10-C20 saturated hydrocarbon. Exemplary acid chlorides include hexadecanoyl chloride and polyethylene acid chlorides.
A cellulosic or other material may be reacted with an activated acyl group such as an acid chloride, R(CH2)2COCl or anhydride, (R(CH2)2CO)2O, wherein R is a C1-C10 fluorocarbon. For example, R may be CF3xe2x80x94, or CF3(CF2)nxe2x80x94 wherein n is, for example, 1 to 10.
In a second step, the material may be further modified in a second reaction with a small organic acid chloride, such as acetyl chloride, to acylate unreacted groups, such as hydroxyls, on the material.
A method of modifying a textile material also is provided comprising reacting the material with an alkyl silane, thereby to covalently attach the alkyl silane to the material. The alkyl silane has, for example, the formula RSiX1X2X3, where R is a hydrocarbon or fluorocarbon, and one or more of X1, X2, and X3 are independently a halo or alkoxy group, and the remainder of X1, X2, and X3 are independently alkyl. In one embodiment, X1, X2, and X3 are independently chloro, ethoxy and methoxy, and the remainder of X1, X2, and X3 are methyl. The material is, for example, a cellulose or wool containing material.
Also is provided a method of modifying a textile material to increase the hydrophobicity of the material, the method comprising crosslinking the material with hydrophobically modified dimethyloldihydroxyethyleneurea. The textile material is, for example, a carbohydrate containing material and the dimethyloldihydroxy-ethyleneurea comprises, for example, a covalently attached hydrocarbon or fluorocarbon group.
Also provided is a method of modifying a cellulosic material, such as a cotton material, the method comprising crosslinking the material with a functionalized glucose molecule comprising a reactive group such as an isothiocyanate, isocyanate, acyl azide, sulfonyl chloride, aldehyde, glyoxal, oxirane, carbonated imidoester, carbodiimide, succinimide ester, epoxide, alkyl halide, anhydride, acid chloride, or an activated ester.
The methods disclosed herein may be used to modify various substrate materials, such as textile fibers of cotton or other cellulosic materials, wool, silk and other proteinaceous fibers, and various other natural, regenerated and synthetic fiber materials to alter and optimize their properties for use in different applications. Materials containing various natural, regenerated, man made and/or synthetic fibers in the form of cloth or fabric of various types may be modified, in order to improve various performance properties such as water resistance, soil resistance, oil or grease resistance, speed of drying and permanent press properties, such as smoothness or wrinkle resistance and xe2x80x9cwash and wearxe2x80x9d.
Materials comprising cellulose may be modified and are described by way of example. A variety of other materials, such as other polysaccharides or polyamines, also may be modified, for example, to improve their hydrophobicity by the covalent attachment of hydrophobic groups. Cellulose containing materials which may be modified include cotton materials and various types of regenerated cellulose, such as rayon, including viscose rayon and lyocell, other natural cellulosics such as linen, ramie and the like, in fiber, yarn or fabric form, which may be either undyed or dyed prior to the reaction. Hydrophobic cellulosic material can be made with selected covalently attached hydrophobic groups to improve properties of the cellulosic substrate such as water resistance and permanent press properties. Proteinaceous fibers including silk, wool, camel""s hair, alpaca and other animal hairs and furs and regenerated protein fibers may be modified, as well as synthetic fibers including polyamides, such as nylon 6 and 66, various polyesters, including polyethylene glycol terephthalate and derivatives thereof and polytrimethylene terephthalate and other synthetic fibers with suitable reactive properties. Various of these types of fibers also can be blended with one or more other fibers, before or after treatment, e.g. cotton or rayon and polyester, or wool and polyester, together, or with silk, linen or rayon added. The modified materials obtained as disclosed herein may be used in a variety of applications, such as the fabrication of clothing and various items of wearing apparel, socks, hosiery, footwear, shoes, home furnishing fabrics including upholstery and window treatments including curtains and draperies, and fabrics for outdoor furniture and equipment, as well as for industrial textile end uses.